21-Jul-2022: Uranium Contamination of Ground Water
Water being State subject, study on groundwater quality and making available safe water to public falls under States’ mandate. However, Central Ground Water Board (CGWB) has carried out a study to map areas with Uranium contaminated ground water during 2019. As per this study, the occurrence of Uranium in ground water beyond the BIS permissible limits (0.03 mg/l) of water was observed in around 409 groundwater samples against 14,377 samples analysed by the CGWB in around 18 States.
The data generated by CGWB has been shared with respective State Governments for taking suitable remedial action. Further, Government of India in partnership with States is implementing Jal Jeevan Mission (JJM) – Har Ghar Jal since August, 2019 to make provision of potable tap water supply in adequate quantity, of prescribed quality and on regular & long-term basis to every rural household by 2024. In addition, under JJM, while allocating the funds to States/ UTs, 10% weightage is given to the population residing in habitations affected by chemical contaminants including heavy metals and while planning for potable water supply to household through tap connection, priority is to be given to quality-affected habitations.
As per Department of Atomic Energy (DoAE), hydrogeological and stable isotope tracer investigations carried out in the groundwater around the Tummalapalle uranium mining project have confirmed that there is no association between uranium mining industry and elevated uranium levels in ground water. The Uranium occurrence is natural which has been confirmed from the investigations.
As per DoAE, it has been established by the scientific investigations that no damage is caused to borewells and crops due to UCIL operations at Tummalapalle.
16-Mar-2020: Uranium Contamination in Ground Water
There is prevalence of Uranium concentration above 30 micro-gram per litre (World Health Organization (WHO) provisional guidelines) in some of the localized pockets of few States/UTs in the country. A report brought out by Duke University, USA in association with Central Ground Water Board and State Ground Water departments states that Andhra Pradesh, Chhattisgarh, Gujarat, Haryana, Himachal Pradesh, Jharkhand, Karnataka, Maharashtra, Odisha, Punjab, Rajasthan, Tamil Nadu, Telangana, Uttar Pradesh, West Bengal and Jammu & Kashmir have localised occurrence of Uranium concentration.
As per information received from Department of Atomic Energy, elevated uranium level in drinking water may affect human health. Health studies carried out elsewhere in the world suggest that elevated uranium level in drinking water may be associated with kidney toxicity. Further, several studies focusing on health effects have been carried out in Finland among people who use their drilled wells as sources of drinking water having uranium concentrations in the range 5.6 – 3410 ppb. However, no clear clinical symptoms have been observed among the exposed population.
The Indian Standard IS 10500: 2012 for Drinking Water specification has specified the maximum acceptable limits for radioactive residues as alpha and beta emitters, values in excess of which render the water not suitable. These requirements take into account all radioactive elements including uranium. No individual radioactive elements have been specifically identified.
Further, as per information provided by Bureau of Indian Standard (BIS), they are working to incorporate maximum permissible limit of Uranium as 0.03 mg/l (as per WHO provisional guidelines) in all drinking water standards after following due process.
9-Jun-2018: Severe uranium contamination in India’s groundwater
While the primary source of uranium is geogenic, anthropogenic factors such as groundwater table decline and nitrate pollution may further enhance uranium mobilisation. Scientists have found widespread uranium contamination in groundwater from aquifers across 16 states in India, much above the WHO provisional standard for the country. The findings published in the journal Environmental Science & Technology Letters are the first to demonstrate the predominant prevalence of uranium in India’s groundwater.
The researchers from Duke University in the US unveiled new data showing that the occurrence in uranium in Indian groundwater — a primary source of drinking water and irrigation — is an emerging and widespread phenomenon.
They compiled data on groundwater uranium from 16 Indian states and new data from 324 wells in Rajasthan and Gujarat that shows a high prevalence of uranium concentrations above the WHO provisional guideline value across India.
The WHO has set a provisional safe drinking water standard of 30 micrograms of uranium per litre for India, a level that is consistent with US Environmental Protection Agency standards. Despite this, uranium is not yet included in the list of contaminants monitored under the Bureau of Indian Standards’ Drinking Water Specifications.
The study suggests that contribution of human factors such as groundwater depletion and nitrate pollution may be aggravating the already present natural uranium contamination to dangerous levels. Several studies have linked exposure to uranium in drinking water to chronic kidney disease.
Nearly a third of all water wells tested in Rajasthan, contained uranium levels that exceed the World Health Organization and US Environmental Protection Agency’s safe drinking water standards. By analysing previous water quality studies, scientists also identified aquifers contaminated with similarly high levels of uranium in 26 other districts in northwestern India and nine districts in southern or southeastern India.
Many of India’s aquifers are composed of clay, silt and gravel carried down from Himalayan weathering by streams or uranium-rich granitic rocks. When over-pumping of these aquifers’ groundwater occurs and their water levels decline, it induces oxidation conditions that, in turn, enhance uranium enrichment in the shallow groundwater that remains.
While the primary source of uranium is geogenic (naturally occurring), anthropogenic (human caused) factors such as groundwater table decline and nitrate pollution may further enhance uranium mobilisation. Using geochemical and uranium isotope data, it suggests factors that may drive high uranium concentrations in groundwater, including uranium content in aquifer rocks, oxidation state, and groundwater chemistry that promotes the formation of soluble uranyl carbonate complexes.
The occurrence of uranium in these groundwater sources depends on several factors. These factors include the amount of uranium contained in an aquifer’s rocks; water-rock interactions that cause the uranium to be extracted from those rocks; oxidation conditions that enhance the extracted uranium’s solubility in water; and the interaction of the extracted uranium with other chemicals in the groundwater, such as bicarbonate, which can further enhance its solubility.
In many parts of India, these factors co-occur and result in high uranium concentrations in the groundwater. Geochemistry and isotopic tools help us to better understand the process and conditions that control uranium occurrence in groundwater.
Human activities, especially the over-exploitation of groundwater for agricultural irrigation, may contribute to the problem. The study strongly suggests the need for revision of the current water quality monitoring program in India, evaluation of human health risks in areas of high uranium prevalence, development of adequate remediation technologies, and, above all, implementation of preventive management practices to address this problem.
Including a uranium standard in the Bureau of Indian Standards’ Drinking Water Specification based on uranium’s kidney-harming effects, establishing monitoring systems to identify at-risk areas, and exploring new ways to prevent or treat uranium contamination will help ensure access to safe drinking water for tens of millions in India.